Libya Montes forms the eroded and cratered remains of the southern rim of the 1100-kilometer-wide Isidis impact basin on Mars. These highlands have been heavily eroded by valley networks draining northward into the basin. This drainage has carved deep valleys (for example, at bottom center), eroded large areas, and deposited sediments in low areas. Valley networks such as these are common throughout the equatorial highlands of Mars and may be a direct result of extended periods of rainfall or melted snowfall early in martian history. At least one crater (oval crater at lower left) appears to have been partially filled by sediment, probably as a result of extensive depositional processes. This crater may possibly have contained a lake of standing water at one time. These features point to a more active erosional history on Mars in the past.
1 images 876A01, 377S79.